// @(#)root/mathmore:$Id$
// Author: L. Moneta, A. Zsenei   08/2005

  *                                                                    *
  * Copyright (c) 2004 ROOT Foundation,  CERN/PH-SFT                   *
  *                                                                    *
  * This library is free software; you can redistribute it and/or      *
  * modify it under the terms of the GNU General Public License        *
  * as published by the Free Software Foundation; either version 2     *
  * of the License, or (at your option) any later version.             *
  *                                                                    *
  * This library is distributed in the hope that it will be useful,    *
  * but WITHOUT ANY WARRANTY; without even the implied warranty of     *
  * General Public License for more details.                           *
  *                                                                    *
  * You should have received a copy of the GNU General Public License  *
  * along with this library (see file COPYING); if not, write          *
  * to the Free Software Foundation, Inc., 59 Temple Place, Suite      *
  * 330, Boston, MA 02111-1307 USA, or contact the author.             *
  *                                                                    *

// Header file for class GSLQuasiRandom
// Created by: moneta  at Sun Nov 21 16:26:03 2004
// Last update: Sun Nov 21 16:26:03 2004
#ifndef ROOT_Math_GSLQuasiRandom
#define ROOT_Math_GSLQuasiRandom

#include <string>
#include <vector>

namespace ROOT {
namespace Math {

   class GSLQRngWrapper;

      Base class for all GSL quasi random engines,
      normally user instantiate the derived classes
      which creates internally the generator and uses the class ROOT::Math::QuasiRandom

      @ingroup Random
   class GSLQuasiRandomEngine {


         default constructor. No creation of rng is done.
         If then Initialize() is called an engine is created
         based on default GSL type (MT)

          create from an existing rng.
          User manage the rng pointer which is then deleted olny by calling Terminate()
      GSLQuasiRandomEngine( GSLQRngWrapper * rng);

         Copy constructor : clone the contained GSL generator
      GSLQuasiRandomEngine(const GSLQuasiRandomEngine & eng);

         Assignment operator : make a deep copy of the contained GSL generator
      GSLQuasiRandomEngine & operator=(const GSLQuasiRandomEngine & eng);

         initialize the generator giving the dimension of the sequence
         If no rng is present the default one based on Mersenne and Twister is created
      void Initialize(unsigned int dimension);

         delete pointer to contained rng
      void Terminate();

         call Terminate()
      virtual ~GSLQuasiRandomEngine();

         Generate a  random number between ]0,1[
      double operator() () const;

         Fill array x with random numbers between ]0,1[
      bool operator() (double * x) const;

         Skip the next n random numbers
      bool Skip(unsigned int n) const;

         Generate an array of quasi random numbers
         The iterators points to the random numbers
      bool GenerateArray(double * begin, double * end) const;

         return name of generator
      std::string Name() const;

         return the state size of generator
      unsigned int Size() const;

         return the dimension of generator
      unsigned int NDim() const;


      /// internal method used by the derived class to set the type of generators
      void SetType(GSLQRngWrapper * r) {
         fQRng = r;


      GSLQRngWrapper * fQRng;                // pointer to GSL generator wrapper (managed by the class)


      Sobol generator
      gsl_qrng_sobol from
      <A HREF="http://www.gnu.org/software/gsl/manual/html_node/Quasi_002drandom-number-generator-algorithms.html#Quasi_002drandom-number-generator-algorithms">here</A>

      @ingroup Random
   class GSLQRngSobol : public GSLQuasiRandomEngine {

      Niederreiter generator
      gsl_qrng_niederreiter_2 from
      <A HREF="http://www.gnu.org/software/gsl/manual/html_node/Quasi_002drandom-number-generator-algorithms.html#Quasi_002drandom-number-generator-algorithms">here</A>

      @ingroup Random
   class GSLQRngNiederreiter2 : public GSLQuasiRandomEngine {

} // namespace Math
} // namespace ROOT

#endif /* ROOT_Math_GSLQuasiRandom */